Circuit breaker



1951 M. G. LEONARD ET AL 2,686,242

CIRCUIT BREAKER Filed July 26', 1952 s Sheets-Sheet 1 Fig.|.

WITNESSES:

INVENTORS Merrill 6. Leonard urgd Arthur M.Lockie.

ATTORNEY 0, 1 54 M. G. LEONARD ET AL 2,686,242

CIRCUIT BREAKER Filed July 26, 1952 3 Sheets-Sheet 3 Fig.4.

an 65 I99 99 IQI'EE 65 209 WITNESSES: INVENTORS j Merrill 6. Leonard and Arthur M.Lockie.

ATTORNE Patented Aug. 10, 1954 UNITED STATES lQiZNT OFFICE 21 Claims. 1

The invention relates to circuit breakers and more particularly to circuit breakers for mounting in transformers to control moderate power distribution on feeder circuits.

An object of the invention is to provide a circult breaker embodying an improved operating mechanism that is simple and rugged in construction. reliable in operation and which can be manufactured and seviced at low cost.

Another object of the invention is to provide a circuit breaker embodying an overload trip mechanism controlled by a thermally responsive element which element also controls an indicato for indicating predetermined overload or temperature conditions.

Another object of the invention is to provide a circuit breaker embodying an overload tripping device and a current indicating tripping device controlled by a single thermally responsive element in which the current indicating tripping device is reset by partial operation of the breaker operating handle without disturbing the breaker contact position.

A further object of the invention is to provide a circuit breaker embodying a self aligning contact structure.

The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in connection with the accompanying drawings.

In said drawings:

Figure 1 is an elevational view of a circuit breaker embodying the principles of the inven tion;

Fig. 2 is a sectional view taken substantially along line II-II of Fig. 1 and looking in the direction indicated by the arrows;

Fig. 3 is a detail elevational View showing the signal latch mechanism and the resetting means therefor;

l is a top plan view showing two circuit breakers of the type illustrated in Fig. 1 mounted together for unitary operations;

Fig. 5 an end elevational view of the circuit breakers shown in Fig. 4 illustrating the handle operating mechanism.

Referring to Fig. 1 of the drawings, the circuit breaker comprises a base or housing memher it of molded insulating material on which are mounted the parts of the breaker mechanisin which include a stationary contact it, a movable contact l5, operating mechanism indicated generally at H and a trip device indicated generally at It. The stationary contact i3 is rigidly mounted on one leg of a generally U- shaped 2! which is biased by a spring 23 to rovide contact pressure in the closed contact position. The spring 23 is compressed between the U-shaped slide 2% and a projec'ion 25 of a central portion 2% of the base or ii. A contact guide 2? is mounted on the ejections a spring clip 29 which resiliently engages the projections 25.

The movable contact is rigidly mounted on a. U-shaped member 3! pivotally mounted by means or a pivot pin 33 on one end of a floating switch arm 35 for limited movement relative thereto to provide contact alignment in the closed contact position. The switch arr. at its upper end (Fig. 1) is formed at right angles as at 3? to provide a latch surface for engaging a latch surface 39 on a pivoted latch mel ber The formed portion 3? of the switch arm 35 also provides a hook (Fig. 2) to which a spring E3 is attached. The other end of the spring 63 is hooked over a spring stud it in the portion 2&3 of the base and the spring biases the switch arm 35 in opening direction about a pivot pin :l'i when the latch member 1% is actuated to release the switch arm.

The switch arm 35 is U-shaped at its lower or contact end, the other arm (Fig. 2) the cof being disposed on the opposite side of the portion 25 of base i i and connected to the switch arm 35 by a yoke portion 59. he portion 35a of the switch arm is not as long as the main switch arm and extends upwardly only far enough to receive the pivot pin 4? (Fig. l). Mounted on the pin 5? between the switch arm 35 and the portion 35c thereof a roller 5| (Figs. 1 and 3) which engages a enerally triangular opening 53 in the p rtion of the base or frame H. The roller 5! is guided between two arcuate guide surfaces 52 and 5d of insulating material at the left end of the opening 53. The surfaces =52 and 54 are generally concentric with the latch portion 39 so that the switch arm 35 is guided for pivotal movement about its end 3'3 and is held against substantial longitudinal movement. A pair of spaced links 55 disposed one on the outside of the switch arm 3-5 and the other on the outside of the portion 35a are pivotally mounted on the pin Ill and are held in place by spring clips (only one being shown). A pin 5% extends through open ings in the other ends of the links and through the opening 53 in the portion 2% of the base ii. A roller iii (Figs. 1 and 2) mounted on the pin 5i; between the links 55 cooperates with an arouate surface 63 of the opening 53.

An operating handle 65 of molded insulating material has an arcuate portion 6! molded integral therewith adapted to slide on an arcuate surface as on the portion 25 of the base ii between an on and an off position. A pair of operating springs "i! (Figs. 1 and 2) have one end hooked over the pin 55 at opposite ends thereof and the other ends of the springs ii are attached to opposite ends of a spring support it which straddles the arcuate portion ti of the operating handle 35. The arcuate portion ti oi the handle 55 is provided with projections '55 7? extending laterally on each side thereof (Figs. 1 and 2). As viewed in Fig. 2, the lower ends or the projections it and i! cooperate with a flange iii of the portion 26 to retain the handle 55 substantially centered on the surface so. For the same purpose the upper ends or the projections it and it are adapted to cooperate with a cover 85 (Fig. 2), there being a cover 85 provided for each side of the base or housing II. he will be seen in Fig. 1, the projections il have inwardly extending projections 83, one on each side of the portion 25, for guiding the handle in its movement on the arcuate surface 59.

In the closed position of the circuit breaker (Fig. l) the line of action of the operating springs ii is below the center indicated at A about which the handle 65 moves, thus biasing the handle to the on position. Also the line of action of the springs ii is below the center indicated at 3 about which the roller 5! travels on the surface as and biases the roller into the lower right hand portion 3:? of the opening 53 and through the links holds the roller iii in the left hand end or the opening 53 (Figs. 1 and 3). lhis action of the operating mechanism, together with the latch ii maintains the switch arm 35 in the closed position.

When the operating handle 85 is moved from the position shown in full lines in Fig. 1 upwardly to the position shown by the dot and dash lines, the line of action of the operating springs ii moves upwardly and at a certain time moves above the center line B-iii. When this occurs, a component of the force of the springs ii biases the roller ii upwardly and causes the roller together with the associate of the links 55 to move upwardly and toward the right with a snap action. The roller iii travels along the arcuate surface it until it is stopped by engagement with the upper right hand end S? of the opening 53. This movement of the roller 6i acts through the links to move the switch arm 35 with a snap action to the open position shown by dot and dash lines in Fig. l, where it is stopped by engagement of the contact end thereof with a portion $5 of the base ii.

The breaker contacts are closed by movement of the handle as from the oil to the on position. During this movement the line of action of the operating springs ii crosses over below the center line 3-5 to whereupon the springs bias the roller 6i downwardly and causes it to move down along the arcuate surface to the lower or full line position with a snap action. This movement or the roller 8i acts through the links til to close the contacts with a snap action. The fact that the opening spring 2 3 acts on the switch arm 35 adjacent its latched end 3? has the advantage that this spring does not have to be overcome by the operating spring "ii on each manual operation, since the end of the switch arm 35 then remains substantially stationary, having only a generally pivotal movement about its end 37.

I'he switch arm 35 is automatically moved to open position by the spring 13 upon actuation of the latch mere er ii which is effected by the trip device is. The latch s! is pivoted on a pin es in the base ii and is biased by a spring st to latching position to releasably restrain the switch arm in closed position. When the latch ll is actuated to unlatohing position, releasing the upper end of the switch arm the spring :23 acts to rotate the switch arm counterclockwise about the pivot pin i to effect pening of the contacts. The switch arm 35 is stopped in its counterclockwise or opening movement by engaging the portion 83 of the base ii. The operating mechanism including the pin l ks 55, springs ii and the operating handle remain in the positions in which they are shown by full lines in Fig. 1 during an automatic opening operation.

In addition to the latch member ll the trip device it: includes a U-shaped latch operator 93 pivoted on a pin 85 and biased by a s :ing. iii in a clockwise direction. One arm of ne latch operator is normally engaged by a latch portion ills of a latch element it! rigidly mounts on the free end of a bimetal element to releasably hold the latch operator in operative position. The other arm We of the latch operator has a projection lil'i thereon adapted to engage an car it?) formed on the end or the latch Si and actuate the latter upon release of the actuator as. The two aims and of the latch operator es, are connected by an integral yoke portion iii to which one end of the spring er is attached, the other end or" the spring ti being hooked over a pin i it in the base i i.

The bimetal element itt is rigidly secured to a yoke member H5, the legs of which are pivotally supported on a pin ii'i mounted in a boss Us on the base ii. One leg iii of the yoke member H5 extends to the right from the pivot iii and has its free end pivotally connected e a pin I23 to the inner end of an adjusting rod which extends out through an opening in the top portion of the base ii and has a internally threaded nut i2! threaded onto the outer end thereof. A spring 429, compressed between a spring seat it: on the base it a spring guide i335 on the leg iii of the yoke member i it, biases the yoke member He and the binietal element in a clockwise direction about the pivot pin ill. The end of the adjusting screw 52? bears against the top wall of the ii by turning the screw iii the bimetal assemblage may be moved either clockwise or t counterclockwise according to the direction the s rew i2? is turned. This varies the amount of overlap of the latch Hi9 and thereby varies the tripping time of the breaker.

A flexible terminal conductor i3 is welded or otherwise mechanically and electrically connected to an angular conductor I31 which is, in turn, similarly connected to the bimetal element I93 adjacent the pivot II1 to connect the breaker in an external circuit. A conductor I39 mounted on the free end or" the bimetal element I03 has one end of a flexible conductor I4I electrically connected thereto, the other end of the conductor i 'll being connected to the U-shaped contact member 32 back of the switch arm as viewed in Fig. 1. Another flexible terminal conductor I43 is connected to the stationary contact slide 2! for connecting the breaker in an electrical circuit. The circuit through the breaker extends from the flexible terminal conductor I35, bracket I31, bimetal element I83, conductor I39, flexible conductor IEI, contact members 3I, movable and stationary contacts I5I9, and contact slide 2| to the other flexible terminal conductor I43.

When an overload current occurs in the circuit through the breaker the bimetal element I93 becomes heated and when heated a predetermined amount, bends upwardly causing the latch I99 to release the latch actuator 93 whereupon the spring 91 snaps the actuator 93 sharply clockwise about pivot 95 causing the projection Iii: to engage the ear I09 on the latch element AI and move this element to unlatching position to release the upper end of the switch arm 35. The spring 43 thereupon moves the switch arm about the pivot 41 to the open position with a snap action.

The mechanism is reset and relatched following an automatic opening operation by moving the handle 65 to the off position. During this movement of the handle the mechanism is actuated to the open position shown by dot and dash lines in Fig. l in the previously described manner. This moves the upper end of the switch arm 35 to the right of the latch surface 39 on the latch member 4i permitting the spring 9i to restore this member to latching position. As the handle 65 approaches the oil position the projection 11 thereon engages a surface I on the latch actuator 93 and rotates the latch actuator counterclockwise to effect relatching of the actuator. The contacts are then closed by movement of the handle to the on position as hereinbefore described.

Means is provided for indicating an overload condition that is not of suflicient magnitude to trip the breaker open but which indicates that the current in the circuit is approaching a dangerous overload condition or that a dangerous overload condition has existed and has cleared itself without tripping the breaker. The indi cating means also indicates that the breaker has been tripped open in response to an overload current.

The indicating means comprises a releasable signal member I41 (Fig. 3) pivotally supported by means of a pivot pin I49 on an adjusting slide I5I. The member Id? is provided with a latch portion I53 which is normally engaged and releasably held by the latch portion I99 of the latch member I :lI carried by the bimetal element I93. An arm .55 of the releasable member M1 is pivotally connected by means of a pivot pin I51 to a slidable contact rod I59 of insulating material. The contact rod I59 is guided for vertical sliding movement by spaced projections I3I on the base II. A tapered bridging contact I63 is threaded into a tapped hole in the upper end of the contact rod I59 and is locked in adjusted positions by means of a lock nut I65. A spring 6. I61 coiled about the pin 95 biases the releasable member I41 in a clockwise direction and upon release of the member I41 moves the contact rod I59 upwardly to engage the bridging contact I93 with a pair of spaced stationary contact members or conductors I69 and thereby establish a circuit for energizing a visual or audible signal means.

The adjusting slide I'5I is disposed for vertical sliding movement between an elongated projection Iii molded integral with the base II and a shoulder I13 also molded on the base. At its upper end the slide I5I has an ear I15 formed thereon through an opening in which extends an adjusting screw I11. A threaded portion of the adjusting screw I11 engages a threaded opening in an angular portion I19 of the slide l'rll and the reduced inner end of the screw I11 bears in an opening in a rib I8I on the base II. The adjusting screw I11 extends out through an opening in the top wall of the base II and the head of the screw bears against the base. A spring I83 coiled about the screw I11 and compressed between a shoulder I85 on the top wall of the base II and the ear I15 of the slide I5I biases the slide I55, the screw I11 and the releasable member M1 downwardly, the position of the parts being determined by the head of the screw I11 bearing against the base II. Rotation of the adjusting screw I11, due to the engagement of the threaded portion thereof with the portion I19 of the slide I51 will move the slide up or down depending on the direction the screw is rotated. This will cause the latch portion I53 of the releasable member I 11 to move relative to the latch portion Iiiil of the latch IIiI thus varying the amount or" latch overlap which varies the unlatching time of the releasable member I I'i.

The releasable member I-iII (Fig. 3) is adjusted by means of the adjusting screw I11 to trip and close the circuit to the indicating or signalling device (not shown) before the trip actuator 93 (Fig. l) is released to trip the breaker. Hence, if an overload current occurs which approaches a dangerous magnitude and trips the releasable signal member I41 (Fig. 3), but which overload current is cleared before it releases the trip actuator 93 (Fig. l), the releasable member I 21 will be actuated by the spring I61 (Fig. 3) and cause the bridging contact I93 to close the signal circuit I69 and energize the indicating or signalling means.

The releasable signal member I41 is reset and relatched following an operation thereof by movement of the handle 65 (Fig. 1) part way toward the off position but without moving the handle far enough to cause opening of the breaker. The releasable member I41 is provided with a curved, downwardly extending arm Ill? having a cam surface I89 on the lower end thereof which is disposed in the path of opening move ment of the projection 11 on the operating handle 65. Upon movement of the handle to an intermediate position, but before it is moved far enough to efiect opening of the breaker, the projection 11 engages the cam surface I89 and cams the arm I81 and the releasable member I41 in a counterclockwise direction to permit reengagement of the latch Hill with the latch portion I53 of the releasable member. This action also moves the contact rod I59 down out of engagement with the contact members I62") and effects deenergization of the signal circuit.

' The operating handle 85 can then be restored to the closed position without having opened the breaker.

Two or more of the circuit breaker units may be assembled and tied together for unitary operation to control a multi-phase circuit. While only a single pole circuit breaker has been described in detail, the breakers to be assembled are identical, hence, only the means for providing unitary operation of two or more circuit breakers will now be described. When two or more breakers are assembled together a single cover plate 8i is disposed between adjacent breakers and a cover plate is mounted on the outsides of the outer breakers of the group as shown in Figs. 4 and 5 of the drawings. The breakers are secured together by means of a plurality of bolts lei having nuts H33 on one end thereof two of which bolts pass through openings (Fig. l) in the bases or housings ii and corresponding openings the cover plates 56. The other two bolts pass through the cover plates 3! only, which extend beyond the bases ii (Fig. l). is viewed in Fig. l, the two bolts which pass through bases ii are disposed adjacent the right side or handle side of the breaker and the two bolts (not shown in Fig. l) which engage the covers at only are at the left of the breaker as viewed in l. The two bolts iiii through the front or handle side of the assembled breakers also serve to secure mounting brackets till to opposite sides of the assemblage. The brackets it'll have formed mounting feet use thereon for mounting the breaker assemblage in position inside the transformer tank.

The trip members 45 of the breakers are tied together by means of an insulating trip bar Zfii (Fig. 1) so tripping operation of the latch member li for one of the breakers in response to an overload current occurring in the related phase circuit will operate the latch members of all of the breakers. The trip bar (Fig. l) is mounted in a channel-shaped portion formed on the end of each trip bar and secured thereto by means of bolts 255 (only one shown). The signal circuit for the assembled breakers comprises a pair of conducting, rods (Fig. l) which extend through all of the breakers to be engaged and bridged by the bridging contact 553 of each of the breakers. The conducting rods ill vary in length according to the number of breakers assembled together.

In order to operate the handles 65 of all of the breakers to simultaneously manually open and close the breakers and to reset the mechanisms of the breakers following an automatic tripping operation the handles are tied together by means or" 2st (Figs. a and 5) which passes through openings all in the handles g. l). Mounted .06. see is a link are which is pivotally connected by a pivot pin 215 to one end of a lever 2 ii. The lever 2 i? is pivotally mounted by means of a pin on an car 225 formed integral with the ri ht hand mounting bracket is? (Figs. i and 5) and has an operating rod 223 connected to its other end. The rod 223 extends outside the transformer tank to permit manual operation of the breakers. Operation of the lever ill will effect manual opening and closing of the contacts of all of the breakers, reset and relatch the mechanisms and reclose the contacts of all of the breakers in the same mannor as was described for the single pole unit.

It is at times essential that the service of a transformer be restored, at least temporarily, immediately after the circuit has been opened by as aw operation of the transformer breaker in response to an overload current. However, there are occasions when it is difficult or impossible to reclose the breaker, especially if the oil has been heated by a long continued overload current or high ambient temperature. This is because the hot oil maintains the bimetal element deflected to its tripping position and the mechanism cannot be relatched. Means is provided for emergency adjustment of the binietal elements from outside the transformer tank to permit the circuit breaker to be closed and latched immediately after a tripping operation and to permit the breaker to temporarily carry a certain per entage of overload current for a predetermined time. This means comprises the pivoted mounting of the bimetal elements and the adjusting screws iZl. Mounted on the adjusting screw or nut 52? for each of the breaker units is an arm 225 (Figs. 1 and i) of insulating material having an opening making a non-slip but adjustable connection with serrations on the nut 52?. The arms 225 are placed over the serrations 225 after the not has been adjusted to give proper tripping, the serrations permitting the arms to be secured to the nut at the proper angle irrespective of t e position to which the nut has been turned. Elie insulating arms 225 of the breaker units are c ec-ted by of a link 22? for unitary moverent and the operating wire 229 of a Eowden cable 223 is attached to one of the several arms 22%. The cable 22s is attached by means of a clamp 223i and screw 233 to the housing 5 l of one of the circuit breakers. The end of the cable 22? is attached to an operl arm (not shown) mounted on a shaft( also not shown) on inside of the transformer tank. shaft may be mounted in a sealed bearing and extends outside the tank and may have an emergeny handle mounted on the outer end thereof.

Operation of the emergen y handle and shaft, neither of which are shown, acts through the Eowden cable 22?; to simultaneously rotate the arms 225 and the screws a predetermined distance in a clockwise direction as viewed in Fig. i. This movement of the adjusting screws it? each of which threade-dly engage a corresponding adjusting rod E25 (only one being shown) causes clockwise rotation of the arm iii and the yoke upon which the bimetal element its is mounted about the pivot l lhis moves the l tch portion to latching position even though the bimetal remains in deflected condition and permits relatching of the mechanism and closure of the breakers. action increases the trip temperature setting of the biine'tal element and requires a greater overload trip the bre -ker. By this emergency adjustment the breaker will carry a given overload for a predetermined time but will still trip out in to higher overload or short circuit currents. After the overload has cleared, the emergency adjusting means may be restored to its original position and the transformer laced back in normal use.

The invention provides a circuit breaker embodying a tripping 'neehanisrn controlled by a thermally responsive elemen ior effect g opening of the breaker contacts under certain over load current or temperature conditions. There is also provided adjusting means for the thermally responsive element to permit relatching the mechanism when the temperature of the sur rounding medium is high and the thermal element is deflected, to provide for emergency service. Means is also provided and controlled by the thermally responsive element for eifecting an external indica on of the approach of a dangerous overload or temperature condition less than required to t the breaker. If the condition which caused the indicating means to function disappears without tripped the breaker, the indicating may be reset by partial operation of the breaker operating handle while the breaker contacts remain closed.

Having described the invention accordance with the provisions of the patent statutes, it is to be understood that various changes and modifications may be made in the structural the of Without departing from the spirit of the in vention.

We claim as our invention:

1. A circuit breaker comprising a housing member of molded insulating material, a stationary contact, a movable switch member a contact thereon for cooperating with said stationary contact, guide means on said housing member, a part movable with said switch member adapted to be moved along said guide means, an actuating member having one end connected to said switch member, a second guide means on said housing member, the other end of said actuating member being adapted to be moved along said second guide means to effect opening and closing movement of said switch member, spring means connected to move said actuating member, and an operating handle connected to operate said spring means,

2. A circuit breaker comprising a. housing member of molded insulating material, a stationary contact, a movable switch member having a contact thereon for cooperating with said stationary contact, guide means molded integral with said housing member, a part movable with said switch member adapted to be moved along said guide means, an actuating member having one end connected to said switch member, a second guide means molded integral with said housing member, the other end of said actuating member being adapted to be moved alon said second guide means to effect openin and closing movement of said switch member, spring means connected to move said actuating member, and an operating handle connected to operate said spring means.

3. A circuit breaker comprising a base of molded insulating material, a stationary contact, a movable switch member having a contact thereon for cooperating with said stationary contact, guide means on said insulating base, a part movable with said switch member adapted to be moved along said guide means, an actuating member having one end connected to switch member, a second guide means on said insulating base, a part on the other end of said actuating member adapted to be moved along second guide means to efiect opening and closing movement of said switch member, an overcenter spring connected to said other end of said actuating member, said overoenter spring being operable to move said actuating member along said second guide means, and an operating handle connected to operate said overcenter spring.

1-. A circuit breaker comprising a base of molded insulating material, a Stationary contact, a movable switch member having contact thereon for ooperating with said stationary contact, guide means molded integral with said base, a part movable with said switch member adapted to move along said guide means, an actuatin member having one end connected to said switch member, a second guide means molded integral with said base, a part movable with the other end of said actuating member adapted to move along said second guide means to eiifect opening and closing movement of said s itch member, an overcenter spring connected to said other end of said actuating member, said overcenter spring being operable to move said actuating member along said second guide means, and an operating handle connected to operate said overcenter spring.

5. A circuit breaker comprising a frame, a stationary contact, a movable switch member having a contact thereon for cooperating with said stationary contact, guide means on said frame, a part movable with said switch member adapted to be moved, an actuating member having one end connected to said switch member, a second guide means on said frame, a part movable with the other end or said actuating member adapted to move along said second guide means to effect opening and closing movement of said switch member, an overcenter spring connected to said other end of said actuating member, said overcenter spring being operable to move said actu ating member along said second guide means, an operating handle connected to operate said overcenter spring, and a third guize on said frame, said operating handle being adapted to be moved along said third guide means.

6. A circuit breaker comprising a frame molded insulating material, a stationary contact, a movable switch member having a contact thereon for cooperating with said stationary contact, guide means molded integral with said frame, a part movable with said switch member adapted to be moved along said guide means, an actuating member having one end connected to said switch member, a second guide means molded integral with said frame, a part movable with the other end of said actuating memb r adapted to be moved along said second g" means to effect opening and closing movement of said switch member, an overcenter spring connected to said other end of said actuating memher, said overcenter spring being operable to move said actuating member along said second guide means, and an operating handle conne d to operate said overcenter spring, and a ti rd guide means molded integral with said frame, said operating handle being adapted to be moved along said third guide means to open and close said switch member.

'7. A circuit breaker comprising a housing member of molded insulating material, a stationary contact, a floating switch member having contact on one end thereof for cooperating with said stationary contact, latch means normaliy releasably engaging and supporting the other end of said floating switch member, guide me 3 on said housing member, a movable with said switch member adapted to be moved along said guide means, an actuator having one end connected to said switch member, a second go means on said housing member, a movable with the other end of said actuator be moved along said second guide means to eff opening and closing movement or" said sw' member, an operating handle connected to 1 said actuator, and a current responsive vice operable to actuate latch means unlatching position to permit movement of switch member to open position.

a floating switch member having a contact adjaone thereof cooperating with said stationary contact, a latch portion normally releasably engaging and supporting the other end of said switch member, a spring having one end attached to the latched end of said floating switch member biasing said switch member in opening direction, guide means molded integral with said base, a part movable with said switch member adapted to be moved along said guide means, an actuator having one end connected to said switch member, a second guide means molded integral with said base, a part with the other end of said actuator adapted to be moved along said second guide means to effect opening and closing movement of said switch member, an operating handle connected to move said actuator, and current responsive means operable to actuate said latch portion to unlatching position to permit movement of said switch member to open position.

9. A circuit breaker comprising a housing member of molded insulating material, a stationary contact, a floating switch member having a corn tact on one end thereof for'cooperating with said stationary contact, a latch portion normally releasably engaging and supporting the other end of said switch member, a spring attached to the supported end of said floating switch member biasing said switch member in opening direction, guide means molded integral with said housing member, a part movable with said switch member adapted to be moved along said guide means, an actuator having one end connected to said switch member, a second guide means molded in tegral with said housing member, a part movable with the other end of said actuator adapted to be moved along said second guide means to effect opening and closing movement of said switch member, an operating handle connected to move said actuator, a third guide means molded integral with said housing member, said operating handle being movable along said third guide means to open and close said switch member, and a current responsive trip device for moving said latch portion to unlatching position to permit said spring to move said switch member to open position.

10. A circuit breaker comprising a base of molded insulating material, a movable switch arm having a contact on one end thereof, a latch nor" mally releasably engaging and supporting the other end of said switch arm, means on said base defining a guide for said switch arm, a member on said switch arm cooperating with said guide for controlling the position of said switch arm in the closed position and for guiding the opening and closing movement of said switch arm, operating mechanism for said switch arm comprising a link having guide means on one end and having the other end pivotally connected to said switch arm, a guide surface on said base for guiding the movement of said one end of said link, an operating handle, and an overcenter spring operable by said handle to cause movement of said guide means along said guide surface to efiect opening and closing movement of said switch arm.

11. A circuit breaker comprising a frame of molded insulating material, a movable switch arm having a contact on one end thereof, a latch portion normally releasably engaging and supporting the other end of said switch arm, a spring biasing th supported end of said switch arm in opening direction, means on said frame defining i2 a guide for said switch arm, a member on said switch arm cooperating with said guide for controlling the position of said switch arm in the closed position and for guiding the opening and closing movement or" said switch arm, operating mecha ism for said switch arm comprising a link having guide means on one end and having the other end pivotally connected to said switch arm, a guide surface on said frame for guiding the movement of said one end of said link, an operating handle, an overcenter spring operable by said handle to cause movement of said guide means along said guide surface to effect opening and closing movement of said switch arm, and a trip element operable to move said latch portion to unlatching position to permit automatic movement of said switch arm to open position.

12. A circuit breaker comprising a housing member of insulating material having a partition wall therein, a movable switch arm having a contact on one end thereof, a latch normally releasably engaging and supporting the other end of said switch arm, means on said par 'tion wall defining a guide for said switch arm, a member on said switch arm extending through said partition wall and coacting with said guide for positioning said switch arm in the closed position and for controlling the movement of said switch arm, operating mechanism for said switch arm comprising an operating handle, an overcenter spring coimected to be operated by said handle to cause opening and closing movement of said switch arm, a link having one end connected to said overcenter spring and the other end pivotaliy connected to said switch arm, and guide means on said partition wall, a part movable with said one end of said linlr cooperating with said guide means for guiding the movement of said one end of said link to effect opening and closing movement of said switch arm.

13. A circuit breaker comprising housing member of insulating material a partition wall therein, a movable switch arm having a contact on one end thereof, a latch normally releasably engaging supporting the other end of said si 'tch arm, means on said partition wall defining a guid for said switch arm, a er on said switch arm coacting with said positioning said switch arm in the closed position and for controlling the movement or said switch arm, operating mechanism. for said switch arm comprising operating a surface on said housing, said handle being to be moved along said surface, a pair of overcenter springs on opposite sides or said parti 'on wall connected to be operated by handle to cause opening and closing movement oi said sw arm, a link having one end connected to said pair of overcenter springs and the other end pivotally connected to said switch arm, and guide means on said partition wall, a part movable with said one end of said link cooperating with said guide means for guiding the movement of said one end of said link to effect opening and closing movement of said switch arm.

14. A circuit breaker comprising a housing of? insulating material having a partition a therein, a movable switch arm having a con t on one end thereof, a latch normally reieasably engaging and supporting the other end o switch arm, means on said partition wall defining a guide for said switch arm, a member on v och arm coasting with said guide for positioning said switch arm in the closed position and for con" trolling the movement of said switch arm, operating mechanism for said switch arm comprising an operating handle, an overcenter spring connected to be operated by said handle to cause opening and closing movement of said switch arm, a pair of links on opposite sides of said oartition wall, a member extending through said partition wall connecting one end of links together and to said overcenter spring, the other end of said links being pivotally connected. to said switch arm, and guide means on said partition wall cooperating with said member extending through the partition wall for guiding the move merit of said one end of said links to effect opening and closing movement of said switch arm, and a trip device operable in response to overload currents to cause said latch to release said switch arm and efiect automatic opening movement of said switch arm.

15. In a circuit breaker comprising a housing of molded insulating mateial, switch member, operating mechanism for efiecting movement of switch member to open and closed positions. operating handle slidable on asurface on said housing, an auailiary device, a plurality of members movable from a normal position to an oper ating position, one of said members when moved being connected to actuate said auxiliary device and the other member when moved bein operative to efiect movement of said switch member to open position, a trip device operable to eiiect movement of said one member to actuate said auxiliary device and further operable to effect movement of said other member to thereby eiiect o; ening movement of said switch member, and said handle when moved a predetermined distance en aging and resetting said one member while said switch member remains in closed position.

15. In a circuit breaker comprising housing of molded insulating material, a movable switch operating mechanism for efiecting movement of said switch member to open and iosed positions including an operating handle, a surface on. said housing, said handle being adapted to be slidably moved along said surface to open and closed positions, spaced conductors supported in said housing, a plurality of members movable from a normal position to an operating position, a bridging contact member connected to be operated by one of said members, said one mein er when moved moving said bridg contact member into bridging contact with spaced conductors, the other of said memhers when moved being operative to effect movement of said switch lileLlbEl to open position, said handle when slidably moved a predetermined tance along s surface engaging and resetting said one member to effect disengagen ent of said bridging contact member from said spaced condu tors while said switch member remains in closed position.

ll. In a circuit breaker comprising a hou i of molded insulating material, relatively mov his contacts operating mechanism therefor, an operating handle of insulating material slidable on a surface molded integral with said housing, a releasable trip member operative when released to effect automatic opening 0.. said contacts, a trio device comprising a bimetal element operable in response to overload currents of predetermined value to release said trip member, a pair of spaced conductors supported in said housing, a biased member releasable by said bimetal element in response to overload currents of lesser magnitude, a bridging contact member operable by said biased releasable member into bridging engagement with said spaced conductors, a slidable member pivotally supporting s id releasable member, means molded inte ral wi '1 said housdefming a ch nnel for slidably said slidable n1 oer, adjusting l ably moving said slidable member to move said releasable member relative to c lot i ment to thereby vary the overload current required to release said rel asable member, and a rejection on said releasable member dispose in the path or" movement of said handle and e; gageable by handle when so handle is moved a predetermined distance in opening rection to reset and relatch said releasable member.

18. A multi-pole circuit breaker comprising a floating switch arm for each pole, each of said switch arms having a contact on one end and a latch releasably supporting the other end, a re" leasable trip member for each pole operable when released to engage and actuate the latch. for the associated pole and permit opening movement of the corresponding switch arm, a trip bar interconnecting the latches ior all of said poles so that upon release of the trip member for any one or" said poles the latches of all of said poles will be operated to effect release of all of said switch arms, a bimetal element for each pole heated in response to overload currents in the circuit of the associated pole and operabl when heated a predetermined amount to release the corresponding trip member, adjusting means for each of said bimetal elements, and means interconnecting the adjusting means for all of said poles for effecting simultaneous adjustment of all of said bimetal elements.

19. A multi-pole circuit breaker comprising a floating switch arm for each pole, each of said switch arms having a contact on one end and a latch releasably supporting the other end, a releasable trip member for each pole operable when released to engage and actuate the latch for the associated pole and permit opening movement of the corresponding switch arm, a trip bar interconnecting the latches for all or" said poles so that upon release of the trip member for any one of said poles the latches of all or" said poles will be operated to effect release of all of said switch arms, a bimetal element for each pole heated in response to overload currents in the circuit of the associated pole and operable when heated at predetermined amount to release the corresponding trip member, adjusting means for each of said bimetal elements, and means interconnecting the adjusting means for all of said poles for effecting simultaneous adjustment of all of said bimetal elements to permit said trip members to be reset and permit said switch arms to be closed while said bimetal elements are hot.

20. In a circuit breaker comprising a switch member and operating mechanism for moving said switch member to open and closed circuit positions, an auxiliary device, a plurality of members each having a latch portion thereon and each being movable from a normal position to an operating position, one of said members when moved actuating said auxiliary device, and the other of said members when moved causing automatic movement of said switch member to open position, a bimetal element having latch means thereon normally engaging the latch portions of said members to restrain said members against movement, said bimetal element being operable in response to overload currents of predetermined value to release said one member and further operable in response to overload currents above said predetermined value to release said other member, adjusting means for adjusting said one member relative to said bimetal element to vary the magnitude of overload current required to release said one member, and adjusting means for adjusting said bimetal element to vary the magnitude of overload current required to release said other member.

21. In a circuit breaker, a trip device comprising tvvo latch members, a single bimetal element engaging and releasably restraining said latch members, an auxiliary device, one of said latch members when released actuating said auxiliary device and the other latch member when released causing automatic opening of said breaker, adjusting means for adjusting one only of said latch members, and separate adjusting means for adjusting said bimetal element to vary the time said bimetal will release said latch members.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,328,767 Adam et a1 Sept. '7, 1943 2,439,511 Green Apr. 13, 1948 

